When a railway vehicle passes through a curved section having a small radius of curvature, a large lateral load is applied between a wheel and a rail. Thus, in a section with a sharp curve, a flange of a wheel on an outer rail side undergoes wear at a leading axle, while a side wear occurs on a rail side.
Accordingly, technologies were developed for reducing wear on a flange of a wheel by applying a lubricant to a flange throat region of a wheel by pressing a solid lubricant, to enhance a state of lubrication of areas of contact between a flange of a wheel and a rail (e.g., Patent Reference 1 and Non-Patent Reference 1).
For example, in Non-Patent Reference 1, it was shown that deployment of a solid lubricant to a flange of a wheel from on-board a railway vehicle is effective in reducing wear on a flange throat region of a wheel.
However, FIG. 3 of Non-Patent Reference 1 only shows a photograph in which a solid lubricant presses against a flange of a wheel, and there is no discussion about a detailed structure for pressing the solid lubricant against the flange of the wheel.
In a hypothetical case wherein a constant pressure system employs a spring to press a solid lubricant against a flange of a wheel, there is a problem in that an increasing amount of costly lubricant is consumed, because the solid lubricant is constantly pressed against the flange of the wheel.
In particular, in the case of a steering truck, the solid lubricant is pressed against the flange of the wheel when traveling through a straight section (See FIG. 3 (a)) as well as when passing through a curved section (see FIGS. 3 (b) and (c)). Therefore, if a solid lubricant is deployed on an outer side of a truck frame in the direction of travel, the pressing force on the wheel flange increases at the outer rail side (see FIG. 3 (b)) which the wheel approaches while passing through a curved section, and wear on the solid lubricant is greater than in the case of an ordinary truck.
In FIG. 3, Reference Numeral 1 is a truck frame, 2 is a wheel axle formed from a wheel 2a and an axle 2b, and 3 is a solid lubricant applied to an outer side in the direction of travel of the truck frame 1 so as to freely make contact with and move away from a flange 2aa of the wheel 2a. Reference Numeral 4 is a spring which presses the solid lubricant 3 against the flange 2aa of the wheel 2a, 5 is an axle box, 6 is an axle spring, and R is a rail.
In Patent Reference 1 there is disclosed a movable technology for reducing wheel flange wear, wherein a solid lubricant is formed integrally with a brake shoe, and the surface characteristics of the flange throat of the wheel are improved by transferring the lubricant to the flange throat region of the wheel when the brake is applied.
However, in the technology disclosed in Patent Reference 1, transfer of the lubricant to the flange throat of the wheel is limited to a period when the brake is applied, so the amount of lubricant consumed is lower than when the lubricant is constantly being pressed against, but there remains a problem in that the lubrication performance is not sufficient.